Polluted water can be
easily cleaned and treated to extract valuable chemicals,

e.g., used in drug
manufacturing. No factories or plants are needed, the sun and

a "magic" powder are
enough. The nearly alchemic transformation is accomplished

due to photocatalysts
studied by researchers from the Institute of Physical

Chemistry of the Polish
Academy of Sciences in Warsaw.

In
many places of the world water is highly polluted by organic chemicals from
industrial wastes. The experiments carried out at the Institute of Physical
Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw prove that the
biomass can be successfully transformed into useful chemicals and fuel. Due to
appropriately selected photocatalysts, the transformation of polluted water
into clean one and chemicals does not require specialized plants and takes
place under conditions that are commonly met in nature.

Catalyst
is a substance that participates in the chemical reaction, speeds its course
and fully recovers after the reaction is completed. In typical catalytic
processes the catalysts are activated at high temperatures, typically of
several hundreds degrees centigrade, often at a significantly increased
pressure.

"Photocatalysts
studied by us differ in many respects from traditional catalysts. They are
activated by light, and the temperature has no significant effect here", says
Dr Juan Carlos Colmenares from the IPC PAS. The reactions with participation of
photocatalysts occur at good exposure to sun rays, at temperature about 30
degrees centigrade and at normal atmospheric pressure – so at conditions
occurring naturally all year round in many equatorial countries.

The
photocatalysts studied at the IPC PAS are solids based on titanium dioxide, TiO2.
The catalysed reaction occurs in a liquid containing organic pollutants. After
the reaction is completed, the catalyst can be isolated almost without losses
and used again.

"My
work resembles somewhat alchemy", jokes Colmenares. "I take a 'magic' powder,
pour it into polluted water, stir and expose to the sun. After several hours, I
get clean water plus chemicals that can be used to make useful things, for
instance drugs".

The
research on photochemical degradation of pollutants has been carried out in the
world already in the late 1960’s. By intensive UV irradiation chemical
compounds with simple structures have been obtained at that time.

The
research pursued at the IPC PAS aims at such a selection of photocatalysts and
reaction conditions that the reaction can occur without using specialized equipment,
and the degradation of biomass stops at a precisely defined stage. With
titania-based photocatalysis the researchers managed to produce carboxylic
acids used, e.g., in pharmaceutical and food industries. It is also possible to
prepare a photocatalyst so as to have the reaction completed and yielding
substances with the simplest structure, such as hydrogen or carbon dioxide. The
latter compound is undesirable and would require disposal, hydrogen, however,
has excellent prospects as the fuel of the future.

"In
laboratory conditions, the reactions of the biomass with participation of
photocatalysts are promising already now. In this year we are going to attempt
the first tests in the pilot biochemical photoreactors at the University of
Cordoba, Spain. The reactions will occur there in liquids with volumes measured
in tens of litres", says Colmenares while making clear that still many tests
and studies are to be carried out before the new technology gets disseminated.

The
co-authors of the paper published in the "Bioresource Technology" journal,
describing application of photocatalysts to glucose degradation and to
production of valuable chemicals are Agnieszka Magdziarz and Dr Anna
Bielejewska, who passed away late last year. The research has been financed
from an international Marie Skłodowska-Curie reintegration grant under the 7th
Framework Programme of the European Union.

This press release was prepared thanks to the
NOBLESSE grant under the activity "Research potential" of the 7th
Framework Programme of the European Union.

The Institute of Physical
Chemistry of the Polish Academy of Sciences (http://www.ichf.edu.pl/) was established in 1955
as one of the first chemical institutes of the PAS. The Institute's scientific
profile is strongly related to the newest global trends in the development of
physical chemistry and chemical physics. Scientific research is conducted in
nine scientific departments. CHEMIPAN R&D Laboratories, operating as part
of the Institute, implement, produce and commercialise specialist chemicals to
be used, in particular, in agriculture and pharmaceutical industry. The
Institute publishes approximately 200 original research papers annually.

Dr Juan Carlos
Colmenares from the Institute of Physical Chemistry of the Polish Academy of Sciences
in Warsaw at the research equipment used in the studies on photocatalysts. (Source: IPC PAS,
Grzegorz Krzyżewski)